1. Field of the Invention
The invention relates to an air pump for generating excess pressure in a fuel tank for liquid fuel for running a portable heating device which is provided with a burner, to which the fuel can be fed from the fuel tank under pressure, the air pump being configured as a reciprocating compressor and comprising: a cylinder fitted on the fuel tank, a piston rod which is disposed coaxially in the cylinder and is axially displaceable, a handle which is designed to actuate the air pump and is supported on the piston rod at an end of the piston rod lying farther from the fuel tank, and a piston which is axially movable in the cylinder and is disposed so as to form a one-way seal and which is fitted at the other end of the piston rod lying closer to the fuel tank and divides the interior of the cylinder into two chambers, of which the one chamber lying closer to the fuel tank communicates with the fuel tank via a one-way valve which lets air enter into the fuel tank but prevents air and/or fuel from escaping from the fuel tank, and the other chamber lying farther from the fuel tank is able to communicate essentially unchecked with the atmosphere, whilst the one-way sealing of the piston against the cylinder permits the passage of air past the piston in the direction from the chamber lying farther from the fuel tank to the chamber lying closer to the fuel tank, but prevents it in the counter-direction.
The heating device provided with the air pump can be used in various variants. One variant thereof can be used for example, in rambling or camping, for cooking purposes (as the flame in a stove), another variant for example, also in rambling or camping, for illumination purposes (as a Welsbach light having an incandescent mantle), yet another variant for example, for craftsmen, for soldering or welding purposes, and yet other variants are also conceivable.
2. Description of the Related Art
An air pump of the stated type is known, for example, for a portable cooking or heating device, from Patent Specification AT-343318. In this known air pump, however, no measure is provided by which the user of the device could be prevented from developing too strong a pressure in the fuel tank by over-lengthy or too often repeated pumping and hence from placing himself and his surroundings, or herself and her surroundings, at risk.